Is This Behavior Normal?

Let’s say that someone you’re in love with confides in you that upon the demise of his last relationship, he was so angry with his ex that, during the 3 weeks they continued to room together after their breakup, he swiped her toothbrush daily on his ass. This confession doesn’t arise out of guilt, rather he seems quite proud of himself. He’s no spring chicken. Would you find this disturbing? Would you believe him? Would it change your feelings for him/her? (This really happened, but I haven’t had the nerve to share it with anyone I personally know. Now I have all of you to run this by, so I’d like to gauge your reaction against mine.) TIA!